Simulation technique for voltage stability Analysis and contingency ranking in power systems

Voltage instability is one phenomenon that could happen in power system due to its stressed condition. The result would be the occurrence of voltage collapse which leads to total blackout to the whole system. Therefore voltage collapse prediction is important in power system planning and operation. Line outage in power system could also lead to the event of voltage collapse which implies the contingency in the system. Line outage contingencies are ranked so that the line which highly affects the system when there is an outage occurs in this line in terms of voltage instability could be identified. The contingency ranking process can be conducted by computing the line stability index of each line for a particular line outage and sort them in descending order. The contingency which is ranked the highest implies that it contributed to system instability. This paper demonstrates a new voltage stability index referred to a line used to rank the line outage contingency. This technique is tested on the IEEE system and results proved that the contingency ranking indicates the severity of the voltage stability condition in a power system due to line outage.